1. Field of the Invention
The present invention relates to the preparation of triethyl dimethyl siloxalane and in particular to the preparation of such a siloxalane from octamethylcyclotetrasiloxane and triethylaluminum.
2. Description of the Prior Art
Alkyl siloxalanes have a variety of uses, including use as a co-catalyst in the polymerization of ethylene and/or other alpha-olefins, as is described in the copending patent application of M. A. Hamilton, D. A. Harbourne, R. Mulhaupt, C. G. Russell and V. G. Zboril, Ser. No. 625,225, filed concurrently herewith and in U.S. Pat. No. 3,969,332 of P. Gloriod et al., issued July 13, 1976.
The preparation of admixtures of triorganosilanes and organosiloxalanes by reacting hexaorganosiloxanes with alkyl aluminum compounds has been described by H. Jenkner in U.S. Pat. No. 2,897,220, issued July 29, 1959. The reaction of octamethylcyclotetrasiloxane and triethyl aluminum to give the ring-opened product (C.sub.2 H.sub.5)(CH.sub.3).sub.2 SiO[(CH.sub.3).sub.2 SiO].sub.2 (CH.sub.3).sub.2 SiOAl(C.sub.2 H.sub.5).sub.2 has been described by H. Jenkner in Zeitschrift fuer Naturforschung 1959 Vol B, p. 133-134.
The preparation of triethyl dimethyl siloxalane by reacting octamethylcyclotetrasiloxane with triethyl aluminum at 50.degree. C. for is described in the aforementioned U.S. Pat. No. 3,969,332. However, as shown hereinafter in the examples, it is believed that octamethylcyclotetrasiloxane and triethyl aluminum do not react at 50.degree. C. to give triethyl dimethyl siloxalane.
A method for the preparation of triethyl dimethyl siloxalane has now been found.